Preparation and properties of mos2 nanosheets and MOS2 nanosheets/epoxy composites

Report the preparation of MoS₂ nanosheets suspensions based on liquid exfoliation method. The suspensions are characterized by absorbance and photoluminescence (PL) spectroscopy. The results show the PL signal from suspensions is enhanced evidently. Meanwhile, obtain the optimized the process conditions which are increasing of ultrasonic time, decreasing of centrifugal rotational speed, using large-size bulk MoS₂ and adding ball-milling process. The PL main peak of single MoS₂ nanosheet is located at 652 nm, which corresponds to a band gap of 1.9 eV. Besides, the single MoS₂ nanosheet is annealed. Because mild annealing could make the lattice distortion in MoS₂ nanosheet which appeared in exfoliation reversed and the semiconducting property of the as-prepared MoS₂ nanosheet is largely restored, the PL signal from single MoS₂ nanosheet is enhanced after annealing. SEM and AFM show the most MoS₂ nansosheets have a lateral size of several hundred nanometers and a thickness of several nanometers. Besides, prepare MoS₂ nansosheets reinforced epoxy composites by mixing MoS₂ nansosheets suspension and E51 epoxy. The PL signal from composites is enhanced as well. That means the MoS₂ nansosheets dispersing in epoxy still keep enhanced PL signal and E51 epoxy could not influence the band gap properties of MoS₂ nansosheets. The composites are annealed. And compared with the composites which are not annealed, the PL signal from annealing composites shows obvious shift which could be ascribed to residual thermal stress in the composites. Meanwhile, the toughness of the composites is also improved, and it is because of the excellent toughness of MoS₂ nansosheets and the dispersion strengthening in the composites.